I want to highlight the cells in which the horizontal and vertical lines are drawn.
Based on what I said before, if you're doing this on an unedited sheet (with default row heights/column widths), then the vertical and horizontal lines are on the
border of two columns and two rows, respectively.
[TABLE="class: grid, width: 350"]
<tbody>[TR]
[TD="align: center"][/TD]
[TD="align: center"]D[/TD]
[TD="align: center"]E[/TD]
[TD="align: center"]F[/TD]
[TD="align: center"]G[/TD]
[TD="align: center"]H[/TD]
[TD="align: center"]I[/TD]
[/TR]
[TR]
[TD="align: center"]9[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
<
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[TD="align: center"][/TD]
[TD="align: center"][/TD]
[/TR]
[TR]
[TD="align: center"]10[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
[/TD]
[TD="align: center"]
<
[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[/TR]
[TR]
[TD="align: center"]11[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
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[TD="align: center"][/TD]
[TD="align: center"][/TD]
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[TR]
[TD="align: center"]12[/TD]
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[TD="align: center"][/TD]
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>
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[TD="align: center"]
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[TD="align: center"][/TD]
[TD="align: center"][/TD]
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[TR]
[TD="align: center"]13[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
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[TD="align: center"][/TD]
[TD="align: center"][/TD]
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[TR]
[TD="align: center"]14[/TD]
[TD="align: center"]
V
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[TD="align: center"]
V
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[TD="align: center"]
>
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[TD="align: center"]
<
[/TD]
[TD="align: center"]
V
[/TD]
[TD="align: center"]
V[/TD]
[/TR]
[TR]
[TD="align: center"]15[/TD]
[TD="align: center"]
^
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[TD="align: center"]
^
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[TD="align: center"]
>
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[TD="align: center"]
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[TR]
[TD="align: center"]16[/TD]
[TD="align: center"]
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[TD="align: center"]
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[TD="align: center"]
>
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[TD="align: center"]
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[TD="align: center"]
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[TD="align: center"]
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[TR]
[TD="align: center"]17[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
<
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[TD="align: center"][/TD]
[TD="align: center"][/TD]
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[TR]
[TD="align: center"]18[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
<
[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[/TR]
[TR]
[TD="align: center"]19[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
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[TD="align: center"]
<
[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[/TR]
[TR]
[TD="align: center"]20[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[TD="align: center"]
>
[/TD]
[TD="align: center"]
<
[/TD]
[TD="align: center"][/TD]
[TD="align: center"][/TD]
[/TR]
</tbody>[/TABLE]
So, illustrated here as best I can, the arrows are pointing to where the lines are created for me. Like I said above, they are in between two rows/two columns.
Will the dimensions of your "square" of data always be an even amount of rows and columns? I obviously don't have any of your data in front of me, but based on the size of the lines you created, I'm assuming that the "square" starts in cell D9 and ends in cell I20 (which is 6 Columns & 12 Rows).